Many implements, such as mower conditioners, are operated by use of a towing vehicle (e.g., tractor) that propels and directs the implement through the field. Rotational power is provided to the implement through a driveline that attaches to the power-take-off (“PTO”) shaft of the towing vehicle. Such implements may be pulled by use of a two-point linkage or a drawbar connected to the towing vehicle. Attachment by use of the drawbar may be easier and faster for the operator relative to use of two-point linkages. When the drawbar is used, a drawbar receiver (synonymously herein “hitch receiver” or “drawbar hitch receiver”) of the implement mates with the drawbar and a hitch pin is used to connect the drawbar to the drawbar receiver. The drawbar receiver is connected to the tongue of the implement.
The implement typically includes a driveline that transfers power from the PTO drive assembly of the towing vehicle to a powered element of the implement. The PTO driveline of the implement connects the PTO shaft of the towing vehicle and a component mounted to the frame of the implement, typically a gearbox assembly mounted on the implement. The PTO driveline is a telescoping assembly with universal joints and shielding that allows relative movement between the towing vehicle and the implement that is inherent with mobile operation.
Mowers are a type of implement that involve frequent sharp turns. These sharp turns require significant angular deviations between the towing vehicle and the implement which can cause similar angular deviations of the PTO driveline. Angular deviations in a PTO driveline can cause various difficulties. A hitch/driveline arrangement commonly referred to as a “swivel gearbox” hitch system has been developed for mowers and mower conditioners.
Such systems include a swivel gearbox assembly that has a vertical shaft, an upper portion that is fixed to the implement's main frame and a lower portion that can pivot about the vertical shaft and that is fixed to a towing frame. The towing frame is configured to be substantially fixed to the drawbar of the towing vehicle when the implement is attached to the towing vehicle. With this arrangement the angular deviation between the towing vehicle and the implement occurs at the axis of the vertical shaft, which is different than other hitch arrangements wherein the angular deviation occurs about the hitch pin. This swivel gearbox hitch system allows the PTO driveline to remain approximately straight, as the angular deviation between the towing vehicle and the implement occurs at the axis of the vertical shaft of the swivel gearbox. This allows the angular deviation between the components of the driveline to occur as the lower gearbox pivots about the axis of the vertical shaft.
A variety of different mechanisms have been developed to utilize this swivel gearbox hitch arrangement, many with relatively complicated mechanisms, or that require relatively complicated assemblies for attaching the towing frame to the towing vehicle drawbar, some having portions that are bolted to the drawbar.
A continuing need exists for drawbar hitch receivers having a towing frame that make hitching simple, that utilize a minimum number of components and that are pivotable relative to the pulling vehicle and the implement to minimize stress between the pulling vehicle and the implement during travel over uneven surfaces, and that adapt to wide variations in the geometry of the drawbar.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.